Waste by-products produced by many industrial processes, and to a lesser extent consumer generated wastes, are often contaminated with toxic organic contaminants and trace metal contaminants. If left untreated, these wastes must be stored in specialized storage containers and deposited in Environmental Protection Agency (EPA) approved landfills to prevent leaching of the contaminants into the ground water. Storage of toxic wastes presents a grave environmental hazard due to the potential for improper storage, or failure of the storage site to contain the toxic leachates. Approved toxic landfill sites are continually growing more scarce, and those remaining are faced with an overwhelming volume of industrially created waste. The costs of shipping toxic waste to the remaining landfills, and fees for interning the waste there, are prohibitive.
Incineration process techniques have been developed over the years in an attempt to treat these toxic wastes by burning off the organic contaminants therein to produce a reduced volume of somewhat less toxic solid waste. The solid waste by-product of such incineration may contain trace metals that failed to oxidize during incineration, and typically must still be handled and stored as a toxic waste. These conventional incineration methods also produced exhaust gas by-products that are toxic in themselves if left untreated, and are harmful to the atmosphere if released.
One example of an industrial waste that must be either decontaminated or stored as a toxic waste is the drilling muds produced by oil industry drilling operations. Drilling muds are gels that are introduced to well bores during drilling of a well to lubricate the drill bit and shaft, and may initially be comprised of water, barite clay, density increasing weighting agents, stabilizers, and an oil base, such as mineral oil. The weighting agents used in these drilling muds may be either mineral or organic materials. During drilling of a well, the drilling mud becomes contaminated with cuttings (bits of rock that have been augered from the earth) and crude oil. In addition, the drilling mud may contain traces of heavy metals that originate from the cuttings, from the weighting agents used in the drilling muds, or from the drilling system itself. The drilling mud is semiliquid in nature and is conventionally stored in reserve pits or boxes as it is produced. Due to the organic and metal contaminants contained therein, the drilling muds must be shipped, handled, and stored as an industrial waste.
The potential utilization of conventional incineration techniques to incinerate drilling mud waste is difficult on a large scale due to the high heat intensity required to melt the minerals contained in the mud and to completely combust the crude oil contaminants contained therein. In addition, the solid by-product that typically results from incineration of such material contains residual trace metal contaminants that still render the waste toxic.